1. Field of the Invention
The present invention relates to a servo drive with high speed wrapping function, especially to a servo drive with high speed wrap, parameter-defined wrap pattern and wire-speed control and controlling method for the same.
2. Description of Prior Art
The controller for wrapping mechanism such as cotton spin cylinder generally uses inverter control architecture. The prior art controller for wrapping mechanism comprises a set of inverter, induction motor and a mechanical transmission device. The induction motor uses the driving control of inverter to provide rotation force for the wrapping mechanism. The lateral movement for the reciprocating operation of the wrapping mechanism is provided by the mechanical transmission device. However, the prior art controller for wrapping mechanism has following drawbacks:
1. The lateral movement is achieved by mechanical transmission and high speed wrapping cannot realize because the mechanical response is limited.
2. The wrapping way has fixed pattern and can not adjusted by parameter. The mechanical structure needs adjustment when other wrapping pattern is required, which is cumbersome.
To overcome the above-mentioned limitation on lateral movement, a set of inverter used with inductor motor is proposed. FIG. 1 shows the frequency wobbling function by the controller for wrapping mechanism. The inverter sets the initial frequency, final frequency and wrapping time parameters. When the inverter receives a running command, a set acceleration time and a holding time for preset wobble frequency is elapsed such that the inverter achieves the central frequency F for wrapping operation. By using the initial frequency and final frequency to set up upper and down wobble frequency, the frequency-wobble time, the frequency-wobble ratio and the jumping frequency are output with respect to time t, whereby the mechanical transmission device is driven by the inductor motor for lateral movement.
The frequency-wobble time=frequency-wobble rise time+frequency-wobble fall time.
The frequency-wobble ratio=frequency-wobble rise time/frequency-wobble fall time.
The jumping frequency=frequency-wobble amplitude×jumping time.
When jumping time≠0, the frequency-wobble period=frequency-wobble time+2×jumping time.
When the inverter receives a stop command, the inverter is decelerated according to a preset deceleration time. The above-mentioned inverter used with inductor motor can provide lateral movement control for wrapping mechanism. However, the actual lateral movement control for wrapping mechanism needs the help of mechanical device for the forward and reverse operation. When the hardware is fixed, the wrapping length is also fixed and the parameter adjustment needs to take hardware into account and the wire speed control is not provided for rotation shaft.